US3994812A - Double bottom tank structure with sleeved strainer means - Google Patents

Double bottom tank structure with sleeved strainer means Download PDF

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Publication number
US3994812A
US3994812A US05/592,655 US59265575A US3994812A US 3994812 A US3994812 A US 3994812A US 59265575 A US59265575 A US 59265575A US 3994812 A US3994812 A US 3994812A
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United States
Prior art keywords
strainer
tubular sleeve
strainer unit
sleeve
unit
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/592,655
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English (en)
Inventor
Bengt H. Nilsson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Uddeholms AB
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Uddeholms AB
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Filing date
Publication date
Priority claimed from SE7409057A external-priority patent/SE383107B/xx
Priority claimed from SE7414368A external-priority patent/SE394798B/xx
Application filed by Uddeholms AB filed Critical Uddeholms AB
Application granted granted Critical
Publication of US3994812A publication Critical patent/US3994812A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J47/00—Ion-exchange processes in general; Apparatus therefor
    • B01J47/02—Column or bed processes
    • B01J47/022—Column or bed processes characterised by the construction of the column or container

Definitions

  • This invention relates to a bottom structure for a tank, and more particularly to a tank bottom structure of the double-bottom type defining a bottom compartment between upper and lower bottom plates and including a plurality of strainer units through which liquid may pass between the bottom compartment and the space above the upper bottom plate.
  • the tank bottom structure supporting the bed often comprises upper and lower bottom plates forming between them a compartment which communicates with the bed through a plurality of strainer units on the upper bottom plate and with piping connected to the lower bottom plate.
  • the bottom compartment is used to collect the treated liquid flowing downwardly through the bed and the strainer units.
  • the treatment is usually carried out periodically or cyclically and the bottom compartment is also used to distribute liquid which is passed upwardly through the strainer units and the bed during the backwashing phases which alternate with treatment phases; the backwashing may serve to regenerate the bed or to remove impurities captured in the bed during the treatment phases.
  • An object of this invention is to provide a bottom structure of the kind indicated in which the strainer units are readily accessible from the outside of the tank, such as from a space below the bottom structure.
  • each strainer unit is disposed in a rigid sleeve which extends between a pair of opposing openings in the upper and lower bottom plates and is rigidly secured, e.g. welded, to the bottom plates.
  • the interior of the sleeve communicates with the bottom compartment through one or more openings in the wall of the sleeve, and the strainer unit has a flow passage which communicates with the bed-containing space above the upper bottom plate through a strainer element and with the opening or openings in the wall of the sleeve.
  • the strainer unit can be inserted in and removed from the sleeve through the lower end of the sleeve.
  • strainer units can thus be readily inspected, adjusted, cleaned and replaced, one can expect that all or almost all strainer units will always function properly at any given time. Consequently, there is no need to provide the strainer units in a number much in excess of the number of properly functioning strainer units that are required to ensure an adequate and sufficiently uniform flow through the bed. This means that the costs can be reduced or that more expensive materials, such as acid-resistant steel, can be used without increasing the costs to an unacceptable level.
  • tank bottom structure Another advantage of the tank bottom structure according to the invention is that the two spaced bottom plates and the several rigidly fastened to the plates form a framework construction which is capable of supporting heavy beds, even if the plates are thin and/or spaced apart only by a small distance. This means that the material economy can be improved still further while at the same time reducing the volume of the bottom compartment and, accordingly, reducing the so-called "tail-effects" occurring on switching between treatment and backwashing phases or on switching from one liquid to be treated to another. These tail effects are caused by liquid remaining in the bottom compartment at the time the switching is effected.
  • FIG. 1 is a fragmentary vertical sectional view of a tank having a bottom structure embodying the invention
  • FIG. 2 is an enlarged vertical sectional view of a portion of the bottom structure shown in FIG. 1;
  • FIG. 3 is a view corresponding to FIG. 2 showing an alternative embodiment of a strainer unit of the tank bottom structure, a restrictor body of the strainer unit being illustrated in a first operating position;
  • FIG. 4 is a view similar to FIG. 3 but showing the restrictor body in a second operating position
  • FIG. 5 and FIG. 6 are horizontal sectional views taken respectively on line V--V and VI--VI of FIG. 3;
  • FIG. 7 and 8 are sectional views corresponding respectively to FIG. 3 and FIG. 4 and showing a modified strainer unit.
  • FIG. 1 shows a portion of a tank forming part of a waste-water treating apparatus.
  • This tank is pressure-tight and includes conduits, not shown, for supplying the waste-water to be treated, for withdrawing treated water, for supplying backwash liquid and for removing the used backwash liquid and washed-off material.
  • the tank 1 includes a cylindrical wall 10 and a bottom structure 2, and it is with this bottom structure the invention is primarily concerned. It forms a support for a sand filter or other bed 3 of powdery or granular material through which the waste-water 4 to be treated is caused to flow downwardly.
  • the tank bottom structure 2 which is circular in plan view, comprises two steel plates 7 and 8 which are flat in the illustrated embodiment but which may alternatively be dished upwardly or downwardly. Regardless of their shape, they are preferably parallel, that is, spaced by a substantially constant distance over the major portion of their area, and placed relatively close to each other so that the volume of the compartment 9 defined between them, hereinafter termed bottom compartment, is small compared with the volume occupied by the bed 3; a preferred maximum ratio of the two volumes is 1:10.
  • the lower bottom plate 7 has a multiplicity of substantially uniformly distributed circular openings 7a, only two such openings being shown in FIG. 1.
  • the upper bottom plate 8 has similar openings 8a, each such opening being aligned with, that is directly opposing, one of the openings 7a.
  • a cylindrical steel sleeve 19 formed by a short length of tubing.
  • the sleeve 19 has its opposite end portions 19a and 19b welded to the two bottom plates 7 and 8 in a fluid-tight manner around the perimeter of the openings 7a and 8a, see FIG. 2.
  • the two spaced bottom plates 7 and 8 and the welded sleeves 19 thus form a framework construction characterized by high load-carrying capacity.
  • Each sleeve 19 has four lateral openings 20 providing constant open communication between the interior of the sleeve and the bottom compartment 9. Liquid can thus flow between the bed-accommodating space of the tank above the upper bottom plate 8 and the bottom compartment through these openings 20.
  • each sleeve 19 has a smaller inner diameter than the lower end portion 19a which is internally threaded as shown at 21 in FIG. 2.
  • the inner surface of the sleeve forms an annular recess 19c in the region of the four openings 20.
  • a strainer body 22 the lower portion of which is externally threaded, is screwed into each sleeve 19 from below and closes the lower end of the sleeve in a fluid-tight manner (in FIG. 1, the strainer body is omitted from one of the sleeves).
  • the upper end portion of the strainer body 22 is provided with an O-ring seal 23 sealingly engaging the inner surface of the upper end portion 19b of the sleeve.
  • a neck 24 of the strainer body 22 projects upwardly beyond the upper end of the sleeve and is provided with external threads.
  • a transverse through passage 25 is formed in the neck 24, and two additional intersecting transverse through passages 26 are formed in the strainer body in the region of the annular recess 19c.
  • An axial passage 27 extends between the transverse passage 25 and the two transverse passages 26.
  • a threaded valve member 28 screwed into the internally threaded lower portion of the axial passage 27 serves to control the flow of liquid through the passage 27 between the passages 25 and 26.
  • the maximum transverse dimension of the strainer element 29 and of the nut 30 is less than the smallest inner diameter of the sleeve 19.
  • the strainer body 22 and the strainer element 29 form a strainer unit generally designated 31 through which liquid can flow both downwardly from the bed 3 to the bottom compartment 9 and upwardly from the bottom compartment 9 to the bed, the flow being controllable by means of the valve member 28.
  • the strainer unit 31 can be screwed into and out of the sleeve without there being any need for access to the bed-accommodating space above the tank bottom structure 2. Thus, adjustments, maintenance and replacement of all strainer units 31 can be carried out from below the tank bottom structure 2.
  • the upper bottom plate 8 is arranged above the lower bottom plate 7 with spacing vertically therebetween to provide a bottom compartment 9.
  • a first plurality of openings 8a is provided through the plate 8 and a second plurality of openings 7a is provided through the plate 7.
  • Respective openings 8a and 7a are in vertical alignment to provide pairs of openings 8a, 7a.
  • Each pair of openings 8a, 7a has a tubular sleeve 19 extending therebetween.
  • Securement means shown as weld material adjacent ends 19a and 19b circumferentially secure the sleeves 19 to the plates 8 and 7 perimetrically of the openings 8a, 7a.
  • Each tubular sleeve 19 has at least one opening 20 laterally therethrough between the plates 8 and 7.
  • Each tubular sleeve 19 is paired with a strainer unit 31 in the sense that one strainer unit 31 is received in each tubular sleeve 19 through the open lower end of the latter.
  • Each strainer unit has an element 29 capable of straining fluid which may endeavor to pass therethrough, interposed in a fluid passage 26, 27, 25 of each strainer unit.
  • One of the two opposite ends of each fluid passage 26, 27, 25 is thus open above the plate 8, i.e. at the strainer element 29 exterior and the opposite end is at 26, for communicating with the bottom compartment 9 via the flow passage 20.
  • Cooperating, disengageable securement means in the form of internal and external threads are respectively provided at 21, for removably securing the strainer units in the respective tubular sleeves.
  • the strainer body 22 of each strainer unit closes the open lower end of the respective tubular sleeve 19.
  • the O-ring seal 23 circumferentially seals between the strainer unit 31 and the tubular sleeve 19 of each strainer unit/tubular sleeve pair 31, 19, above the respective opening 20.
  • strainer units 31 are always easily accessible and replaceable, it is possible to ensure that all or almost all strainer units function properly at any given time. Thus, there is no need to provide the strainer units in a number that is much in excess of the number of properly functioning units required to ensure that the bed will pass the anticipated flow of liquid and that this flow is distributed over the cross-section of the bed with sufficient uniformity.
  • the lower bottom plate 7 For draining the treated liquid collected in the bottom compartment 9 as well as for supplying backwash liquid to the bottom compartment 9, the lower bottom plate 7 has a number of additional circular openings 32.
  • a conical tubular connector 13 is welded to the lower bottom plate 7 around each opening 32 and communicates with a drain conduit, not shown, through a tube 14.
  • the tube 14 also serves to feed backwash liquid to the bottom compartment 9 during the backwashing phases.
  • the water 4 to be treated percolates through the bed 3 and is collected in the bottom compartment 9 through the strainer units 31 and is then discharged through the tubes 14.
  • Backwash fluid liquid and air
  • the strainer units 31 which thus serve as nozzle units during the backwash phases.
  • the invention is not restricted to any particular type or shape of the tank provided with the bottom structure according to the invention.
  • tank as used in this specification is to be understood as embracing many different types of vessels or containers suitable for containing a bed of particulate material.
  • the backwash flow is substantially greater than the liquid flow through the bed during the treatment phases.
  • the embodiments of the strainer units shown in FIGS. 3 to 8 permit an increase of the liquid flow during the backwash phases by increasing the cross-sectional flow area on switching from the treatment phases to the backwashing phases.
  • FIGS. 3 to 8 those parts which are identical with or similar to the parts of the embodiment shown in FIG. 2 bear the same reference numerals as in FIG. 2.
  • the two embodiments shown in FIGS. 3 to 8 differ from the embodiment shown in FIG. 2 only in respect of the strainer units.
  • the strainer unit 40 comprises an externally threaded strainer body 41 screwed into the sleeve 19, which is provided with internal threads 21 in the lower portion, and a strainer element 42 screwed into the upper portion of the strainer body 41.
  • the lower end of the strainer body 41 has a hexagonal wrench socket 43.
  • a pair of O-rings 23 provide a fluid-tight seal between the outer surface of the strainer body and the inner surface of the sleeve 9. Between the two O-rings 23 the strainer body 41 has a waist portion in which two diametral intersecting passages 44 are provided, which open into the annular recess 19c and into a circular opening defined by an upwardly facing annular seat surface 45.
  • the strainer element 42 is shaped like a tubular cap having a rounded top wall 46 and a cylindrical side wall 47. Both walls are provided with a large number of circumferentially distributed narrow slits 48.
  • a tubular restrictor body 49 the lower end of which has an annular face adapated to sealingly engage the seat surface 45 as shown in FIG. 3.
  • a calibrated opening 50 extends axially through the restrictor body 49 and in the position of the restrictor body shown in FIG. 3 forms the only path on which liquid can flow between the passages 44 and the slits 48.
  • the restrictor body 49 is coaxial with, and has a slight clearance to, the inner surface of the strainer element 42. It is displaceable axially, that is, in the vertical direction, in the strainer element from the position defined by the seat surface 45 (FIG. 3) to a position adjacent the top wall 46 defined by a number of lugs 51, see FIG. 4. As is apparent FIG. 4, the restrictor body 49 in the upper position causes no or only a very small restricting action on the upward flow of liquid through the strainer unit.
  • the restrictor body 49 is in the lower position shown in FIG. 3, in which it substantially restricts the downward flow of treated liquid through the strainer unit.
  • the direction of flow of the liquid is reversed, so that the liquid pushes the restrictor body to the upper position shown in FIG. 4 in which almost all liquid bypasses the restrictor body.
  • the restrictor body is returned to the lower position by gravity. The repeated movements up and down of the restrictor body also reduces the tendency of the slits 48 to become clogged.
  • the rate of flow and the pressure drop of the downward flow which are desired in each particular case can easily be achieved.
  • a uniform distribution of the liquid flow can be achieved.
  • the restrictor body 49 as well as the strainer body 41 and the strainer element 42 are suitable made of plastics, although acid-resistant steel or other materials may also be used.
  • the modified strainer unit 55 shown in FIGS. 7 and 8 differs from the strainer unit 40 of FIGS. 3 to 5 only in that the strainer body and the strainer element are made as an integral part 56.
  • the upper end of the cylindrical strainer element is closed by a cover 57 which defines the upper, bypassing position of the restrictor body 49.
  • the strainer unit 55 is practically identical with the strainer unit 40.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtration Of Liquid (AREA)
  • Treatment Of Water By Ion Exchange (AREA)
US05/592,655 1974-07-10 1975-07-02 Double bottom tank structure with sleeved strainer means Expired - Lifetime US3994812A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
SE7409057A SE383107B (sv) 1974-07-10 1974-07-10 Anodning innefattande en silkropp
SW7409057 1974-07-10
SE7414368A SE394798B (sv) 1974-11-15 1974-11-15 Anordning vid silkropp
SW7414368 1974-11-15

Publications (1)

Publication Number Publication Date
US3994812A true US3994812A (en) 1976-11-30

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ID=26656506

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/592,655 Expired - Lifetime US3994812A (en) 1974-07-10 1975-07-02 Double bottom tank structure with sleeved strainer means

Country Status (7)

Country Link
US (1) US3994812A (fi)
JP (1) JPS5133318A (fi)
BR (1) BR7504311A (fi)
CA (1) CA1051358A (fi)
ES (1) ES439257A1 (fi)
FI (1) FI58263C (fi)
NO (1) NO752410L (fi)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5976370A (en) * 1997-07-07 1999-11-02 Westech Engineering, Inc. Underdrain structure for media filters
US5975257A (en) * 1996-09-04 1999-11-02 Komatsu Mining Systems Inc. Method and apparatus for separating steering oil and brake cooling oil within a hydraulic tank
WO2000005174A1 (en) * 1998-07-23 2000-02-03 Seh America, Inc. Resin trap device for use in ultrapure water systems
US8038877B2 (en) * 2007-05-22 2011-10-18 Ibs Filtran Kunststoff-/Metallerzeugnisse Gmbh Oil filter apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59123511U (ja) * 1983-02-09 1984-08-20 オルガノ株式会社 充填物支持床板の集配水機構

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR926950A (fr) * 1946-05-15 1947-10-15 Perfectionnements aux filtres à sable
US2528062A (en) * 1948-02-12 1950-10-31 Dorr Co Liquid-permeable tank bottom for beds of granular material
DE841443C (de) * 1949-10-25 1952-06-16 Cornelis Wichert Hulsbergen Rueckspuelbares Fluessigkeitsfilter
FR1102586A (fr) * 1954-04-08 1955-10-24 Cie Des Eaux Et De L Ozone Perfectionnements aux filtres à sable
US2772780A (en) * 1951-07-17 1956-12-04 Socony Mobil Oil Co Inc Apparatus for contacting liquids with granular solid materials
FR1219918A (fr) * 1959-01-29 1960-05-20 Crépines pour filtres rapides
US3081877A (en) * 1957-08-20 1963-03-19 Steinmueller Gmbh L & C Filter nozzle
US3642205A (en) * 1969-04-25 1972-02-15 Orlando Marty Nozzle for two opposite flow directions with different flow cross sections, and application thereof
US3648731A (en) * 1970-10-26 1972-03-14 Crane Canada Ltd Underdrain
US3869381A (en) * 1972-04-04 1975-03-04 Dwars Ing Bureau Process and apparatus for chemical conditioning of water

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR926950A (fr) * 1946-05-15 1947-10-15 Perfectionnements aux filtres à sable
US2528062A (en) * 1948-02-12 1950-10-31 Dorr Co Liquid-permeable tank bottom for beds of granular material
DE841443C (de) * 1949-10-25 1952-06-16 Cornelis Wichert Hulsbergen Rueckspuelbares Fluessigkeitsfilter
US2772780A (en) * 1951-07-17 1956-12-04 Socony Mobil Oil Co Inc Apparatus for contacting liquids with granular solid materials
FR1102586A (fr) * 1954-04-08 1955-10-24 Cie Des Eaux Et De L Ozone Perfectionnements aux filtres à sable
US3081877A (en) * 1957-08-20 1963-03-19 Steinmueller Gmbh L & C Filter nozzle
FR1219918A (fr) * 1959-01-29 1960-05-20 Crépines pour filtres rapides
US3642205A (en) * 1969-04-25 1972-02-15 Orlando Marty Nozzle for two opposite flow directions with different flow cross sections, and application thereof
US3648731A (en) * 1970-10-26 1972-03-14 Crane Canada Ltd Underdrain
US3869381A (en) * 1972-04-04 1975-03-04 Dwars Ing Bureau Process and apparatus for chemical conditioning of water

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5975257A (en) * 1996-09-04 1999-11-02 Komatsu Mining Systems Inc. Method and apparatus for separating steering oil and brake cooling oil within a hydraulic tank
US5976370A (en) * 1997-07-07 1999-11-02 Westech Engineering, Inc. Underdrain structure for media filters
WO2000005174A1 (en) * 1998-07-23 2000-02-03 Seh America, Inc. Resin trap device for use in ultrapure water systems
US6183637B1 (en) 1998-07-23 2001-02-06 Seh America, Inc. Resin trap device for use in ultrapure water systems and method of purifying water using same
US6416669B1 (en) 1998-07-23 2002-07-09 Seh America, Inc. Resin trap device for use in ultrapure water systems and method of purifying water using same
US6475385B1 (en) 1998-07-23 2002-11-05 Seh America, Inc. Resin trap device for use in ultrapure water systems and method of purifying water using same
US8038877B2 (en) * 2007-05-22 2011-10-18 Ibs Filtran Kunststoff-/Metallerzeugnisse Gmbh Oil filter apparatus

Also Published As

Publication number Publication date
FI58263B (fi) 1980-09-30
CA1051358A (en) 1979-03-27
BR7504311A (pt) 1976-07-06
FI58263C (fi) 1981-01-12
FI751953A (fi) 1976-01-11
NO752410L (fi) 1976-01-13
ES439257A1 (es) 1977-05-16
JPS5133318A (fi) 1976-03-22

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